He began his career creating wire sculptures, which were often stylized animal representations. However, he soon began to explore movement and space, creating mobile sculptures that moved with the wind or the movement of the observer.
Calder's mobiles were complex compositions of abstract, colorful forms, suspended by fine wires and balanced to allow delicate, graceful movement. Calder's mobiles became famous in the 1940s and 1950s and were widely exhibited in museums and galleries around the world.
In addition to his mobiles, Calder also created monumental sculptures and stabiles (static sculptures) in metal. He also worked on public art and stage design projects, creating sets for ballets and operas.
Alexander Calder is considered one of the most important artists of the abstract art movement and is recognized for his innovation and contribution to modern art.